The present invention relates to a disk drive, and more particularly, to control of an airflow generated by rotation of a recording disk in a disk drive.
Data storage devices using various types of media such as optical disks and magnetic tapes are known in the art. Among them, hard disk drives (hereinafter referred to as HDDs) have become popular as storage devices for computers to such an extent that they are one type of the storage devices indispensable for today's computers. Further, not limited to computer systems, HDDs are expanding more and more in application because of their excellent characteristics. For example, HDDs are used for moving picture recording/reproducing devices, car navigation systems, cellular phones, and removable memories for use in digital cameras.
Each magnetic disk used in an HDD has a plurality of tracks formed concentrically and each track is divided into a plurality of sectors. Servo data and user data are stored in each of the sectors. A spindle motor rotates the magnetic disk and a head element as a thin film element makes access to a desired address position in accordance with the servo data stored in a sector, whereby it is possible to effect write or read of data to or from the magnetic disk.
Head element portions are fixed to a slider and constitute a head. The slider flies above a rotating magnetic disk to thereby enable positioning of the head or head element portions to a desired position on the magnetic disk. In data read processing, a signal read from the magnetic disk by a head element portion is subjected to predetermined signal processing such as waveform shaping or decoding processing by a signal processing circuit and is transmitted to a host. The data transferred from the host is subjected to predetermined processing by the signal processing circuit, after which it is written in the magnetic disk.
The HDD has a problem with an airflow generated by rotation of the magnetic disk. For example, the airflow causes an actuator to flutter, which obstructs accurate positioning of a head. In order to suppress the vibration of the head caused by turbulence of an airflow, for example, Patent Reference 1 (Japanese Patent Laid-open No. 2004-171674) discloses a magnetic disk device in which a straightening plate is provided on a ramp in order to suppress the vibration of the head caused by turbulence of an airflow.
The HDD has another problem of vibration of a magnetic disk (disk flutter) caused by the turbulence of an airflow generated by rotation of the magnetic disk. The disk flutter obstructs accurate positioning of the head to the track, similar to the vibration of the head itself. In particular, an increase in recording density of the magnetic disk raises TPI (Track Per Inch), which requires more accurate positioning of the head. Thus, slight disk flutter poses a great problem.